This invention relates to a door system, particularly for a passenger plane and, more particularly, to a door system including a bearing and guiding device acting between the door leaf and the door frame. A lifting device is arranged between the bearing and guiding device and the door leaf. The lifting device moves the door leaf at the end of the closing movement transversely to the moving path of the guiding device with a form-locking engagement with door-frame-fixed receiving elements into a completely closed position. At the start of the opening operation, the lifting device moves the door in the opposite lifting direction out of the form-locking engagement. The lifting device contains lifting kinematics for the control of the door leaf lifting movement and an assigned lifting drive.
Known swing-open door systems of this type, as they are used in modern passenger planes such as the airbus family, are of the so-called "plug type"; i.e., in the completely closed position, the door leaf is lowered by means of edge-side, door-leaf-fixed contact mountings in a form-locking engagement with corresponding abutments fastened to the fuselage structure in the area of the door cut-out. This is done in order to transmit the high pressure forces, which, as a result of the pressure difference between the interior and exterior cabin pressure, act upon the door leaf during the flight. The forces are transmitted directly and without the insertion of mechanically moved locking elements, from the door leaf to the fuselage structure. As a result, the forces prevent the springing-open of the door when there is a failure of the locking mechanism.
For the opening operation, the door leaf must first be lifted out of the form-locking engagement with the abutments before, subjected to the control of a bearing and guiding device acting between the door leaf and the fuselage structure, it will then be swung open out of the door cut-out toward the outside. This movement is essentially perpendicular to the lifting movement. The door will then be moved in the lateral direction in parallel to the fuselage into the full opening position.
For safety reasons, these known door systems have no outside-energy-operated, electric or pneumatic lifting drives. Instead, the lifting movement is mechanically caused purely by means of a manually operated lifting mechanism in the form of a lifting linkage. The lifting linkage is arranged on the interior side of the door leaf and is connected, by means of a lifting-power-boosting torsion spring drive, on the one side, to a four-bar linkage and, on the other side, to an operating lever situated on the exterior and interior side of the door leaf. The four-bar linkage acts between the door leaf and the bearing and guiding device and controls the lifting movement. So that, as a result of vibration and shock effects, the door leaf cannot by itself move out of the fully lowered lifting position and therefore be released from the form-locking engagement with the fuselage-fixed abutments, locking elements are also provided within the scope of the lifting linkage on the edge side on the door leaf. By these means, the door leaf is locked in the completely closed position in a non-liftable manner on the door frame. In the case of such a door system, it is a problem that a large number of very precise and stable linkage parts are required for the lifting linkage, and correspondingly high weight and mounting expenditures are needed such that the manufacturing costs and mainly the total weight of such a door system becomes undesirably high.
There is therefore needed a door system of the above-mentioned type which meets high safety requirements and nevertheless has a mechanically simple construction and a clearly reduced dead weight.
According to the present invention, these needs are met by a door system including a bearing and guiding device acting between the door leaf and the door frame. A lifting device is arranged between the bearing and guiding device and the door leaf. The lifting device moves the door leaf at the end of the closing movement transversely to the moving path of the guiding device with a form-locking engagement with door-frame-fixed receiving elements into a completely closed position. At the start of the opening operation, the lifting devices moves the door in the opposite lifting direction out of the form-locking engagement. The lifting device contains lifting kinematics for the control of the door leaf lifting movement and an assigned lifting drive. The door leaf is provided with an electric drive unit for the lifting drive and a mechanical lift securing device which can be released in parallel to actuation of the electric control of the lifting drive by a door opening command, and locks the lifting device in the completely closed position automatically in a door-leaf-fixed manner.
According to the present invention, as a result of the claimed combination of an electric lifting drive and a mechanical lift securing device, the strict safety requirements for a passenger plane door system are fully met. This is because of the fact that the lift securing device has priority over the electric lifting drive and the lift securing device and the lift drive within the system and, with respect to functions, are completely separated from one another. They can be coupled with one another only externally by means of a door opening command so that a faulty control of the electric lifting drive within the system cannot spread to the lift securing device. An additional aspect with respect to safety requirements is that, because of the dual, on the one hand, electrical and, on the other hand, mechanical lift control, the risk of a faulty door opening lift caused by a purely mechanical or a purely electrical system disturbance is effectively counteracted.
Based on this safety concept, a considerable constructional simplification and weight reduction is achieved by the fact that high-expenditure transmission linkages for the lift driving forces and for the door-frame-side non-liftable locking of the door leaf in the completely closed position are eliminated. Instead, the lift securing device which, because of its self-locking effect also takes over the task of the door leaf locking, together with the singular electric drive unit, is connected directly to the lifting kinematics on the door leaf. Therefore, for the actuating of the lift, in addition to the uncomplicated electric wiring of the lifting drive, only a slightly loaded and therefore low-weight and low-cost releasing mechanism for the lift securing device is required. This ensures an easy and fast operation of the door system.
In order to provide a space and weight saving construction, the lifting kinematics preferably consist of a four-bar linkage arranged between the bearing and guiding device and the door leaf. An electric linear actuator is provided as a lifting drive which acts on a diagonal of the four-bar linkage.
In the case of a complete power failure of the primary current supply as well as of the standby current supply, or in the case of another electric disturbance of the lifting drive, in order for the door leaf to be lifted at least once without any effort from the "plug position", in another, particularly preferred embodiment of the invention, a self-supplying emergency lifting drive is provided on the door leaf in addition to the electric drive. The self-supplying lifting drive consists of a compressed-air motor which is arranged in addition to the electric drive unit and is activated by an emergency opening command with the simultaneous clearing of the lift securing device. The self-supplying unit has an assigned compressed-air accumulator which is preferably fixed to the door leaf. In order to secure the door leaf not only in the lowered, completely closed position, but also during the swinging-open in the lifted position with respect to a faulty activation of the electric lifting drive, the lifting device is preferably in both lift end positions by means of the lift securing device automatically locked fixed to the door leaf.
For the simultaneous control of the mechanical lift securing device and of the electric lift drive, it is expedient that at least on the interior side of the door leaf, a hand lever is provided which is connected with the lift securing device by way of a clearing linkage. The hand lever controls the lift drive by way of electric contacts.
Advantageously, the door may preferably be operated from both sides of the door leaf independently of one another. For this purpose, the door leaf is provided with a door-leaf-interior-side and a door-leaf-exterior-side hand lever. Being mutually mechanically uncoupled, the two hand levers are jointly connected to the clearing linkage of the lift securing device.
Finally, a constructionally particularly robust and mechanically simple further embodiment of the lift securing device consists of the fact that this lift securing device includes a locking disk which is provided with at least one locking element, is coupled with the lifting device in a rotationally fixed manner, and is rotated during a lifting movement about a door-leaf-fixed axis. It also includes a locking lever which is disposed on the door leaf, interacts in at least one lifting end position automatically under prestress with the locking element and locks the locking disk non-rotatably on the door leaf. The locking lever can be withdrawn by means of the release mechanism of the lift securing device from the engaging position with the locking element.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.